How to edit/read pixel values in OpenCv from Mat variable?

Question

I am looking for an efficient way for editing/reading pixels from Mat (or Mat3b) variable.

I have used :-

Image.at(i,j)

Answer 1

This is one of the most efficient way for editing/reading pixels from cv::Mat. Create pointer to a row (of specific channel if needed)

for(int i=0; i*/(i);
  for(int j=0; j